Problem: In math class, the girl to boy ratio is $7$ to $6$. If there are $12$ boys, how many girls are there?
A ratio of $7$ girls to $6$ boys means that there is a group of $7$ girls for every group of $6$ boys. If there are $12$ boys, then there are $2$ groups of $6$ boys each. Because we know the ratio is $7:6$ , there must be $2$ groups of $7$ girls each. There is a total of $14$ girls in math class.